1. Field of the Invention
The present invention relates to an abnormality monitoring device for a motor control system and, more particularly, to an abnormality monitoring device for monitoring an abnormality of a motor control system on a vehicle.
2. Description of the Related Art
Prior engines have employed abnormality monitoring devices with electronically-controlled throttle valves to detect for malfunction. An example of such is disclosed in Japanese Patent Application Laid-Open No. 06-307274 in which an abnormality monitoring device is employed with an electronic throttle system that includes a driving means to open the throttle valve and an associated controller. The monitoring device is used to determine whether the controller is functioning abnormally by monitoring for situations where at least a preset difference is generated between an actual throttle valve opening (actual driving state) of the driving means and a throttle valve opening (predicted driving state) predicted from a depressed amount of an accelerator (e.g., a pedal). If the abnormality monitoring device detects such a situation, the controller stops the driving means.
However, in the above-described conventional abnormality monitoring device described in Japanese Patent Application Laid-Open No. 06-307274, it is judged that the control means is abnormal in a case where the certain or more difference is generated between the actual throttle valve opening (actual driving state) and the predicted throttle valve opening (predicted driving state). Therefore, when the judging of the abnormality is delayed, the throttle motor abnormally operates to abnormally operate the throttle valve by the abnormality of the control means, and there is a possibility that an abnormal behavior is generated in a vehicle.